Conventional chewing gum generally includes gum base composed of ester gum, polyvinyl acetate, latex acids, natural and/or synthetic rubbers, waxes, texturizers and bulking agents; water-soluble flavoring and water-soluble sweeteners, for example, various sugars such as sucrose and dextrose, and/or artificial sweeteners such as sodium or calcium saccharin, cyclamates, dihydrochalcones, glycyrrhizin, glycyrrhizinates; emulsifiers such as lecithin, mono- and diglycerides, and flavors. Such gum initially provides a desirable strong sweet taste which declines rapidly during the first three to five minutes of chewing to a very slight perceptible level of sweetness and flavor. The result is that after about five minutes of chewing all that remains in the mouth is an essentially tasteless wad which provides little in the way of flavor, aroma or sweetness. Accordingly, there clearly is a need and long-felt want for a chewing gum which possesses long-lasting flavor and sweetness.
It has been found that the sweetness and flavor of chewing gums such as non-sour flavored (mint), fruit flavored and sour chewing gums can be prolonged by incorporating or entrapping an artificial sweetener and/or flavor in the ester gum component of the gum base portion of the chewing gum. The artificial sweetener and/or flavor are thereby substantially retained in the gum base and during chewing undergo slow and controlled release into the saliva.
It is important in the above chewing gum that artificial sweeteners and/or food acids which are relatively insoluble, such as free saccharin acid, fumaric acid, adipic acid and succinic acid remain in the gum base for as long as possible without being solubilized therefrom. However, it has been found that where conventional gum base compositions, that is, those gum bases containing calcium carbonate (chalk) as a filler and/or texturizing agent are employed in forming the chewing gum, the chewing gum tends to lose its sweetness retention properties after a few weeks of shelf storage at room temperature. Apparently, during storage, the free acid form of saccharin and the above-mentioned food acids react with the chalk in the gum base to form the calcium saccharin salt and corresponding calcium salts of the food acids which are solubilized from the chewing gum substantially faster than the free acids themselves. Thus, it is preferred that conversion of the free saccharin acid and food acids to a soluble salt should be avoided where possible.